leetcode 1721. 交换链表中的节点
作者:互联网
给你链表的头节点 head 和一个整数 k 。
交换 链表正数第 k 个节点和倒数第 k 个节点的值后,返回链表的头节点(链表 从 1 开始索引)。
示例 1:
输入:head = [1,2,3,4,5], k = 2
输出:[1,4,3,2,5]
示例 2:
输入:head = [7,9,6,6,7,8,3,0,9,5], k = 5
输出:[7,9,6,6,8,7,3,0,9,5]
示例 3:
输入:head = [1], k = 1
输出:[1]
示例 4:
输入:head = [1,2], k = 1
输出:[2,1]
示例 5:
输入:head = [1,2,3], k = 2
输出:[1,2,3]
提示:
链表中节点的数目是 n
1 <= k <= n <= 105
0 <= Node.val <= 100
来源:力扣(LeetCode)
链接:https://leetcode-cn.com/problems/swapping-nodes-in-a-linked-list
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/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode() {} * ListNode(int val) { this.val = val; } * ListNode(int val, ListNode next) { this.val = val; this.next = next; } * } */ class Solution { public ListNode swapNodes(ListNode head, int k) { ListNode f = new ListNode(0); f.next = head; ListNode a = f; int n = 1; while (n < k) { a = a.next; n++; } ListNode b = f; ListNode c = a.next.next; while (c != null) { b = b.next; c = c.next; } c = a.next; a.next = b.next; b.next = c; a = a.next; b = b.next; c = a.next; a.next = b.next; b.next = c; return f.next; } }
标签:head,ListNode,val,示例,next,链表,1721,leetcode 来源: https://www.cnblogs.com/wangzaiguli/p/14767569.html